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At least 73 records · Page 4Linked to original sources
PubMed1992

Nitric oxide production in endotoxin-resistant C3H/HeJ mice stimulated with flavone-8-acetic acid and xanthenone-4-acetic acid analogues.

The production of nitric oxide in endotoxin-resistant C3H/HeJ mice in response to flavone-8-acetic acid (FAA), derivatives of xanthenone-4-acetic (XAA), endotoxin and recombinant human tumour necrosis factor-alpha (TNF-alpha) was investigated and compared with the induction of haemorrhagic necrosis in subcutaneous M16/C tumours. FAA and XAA analogues stimulated nitric oxide production both in vitro (activated macrophages) and in vivo (plasma nitrate elevation) in both C3H/HeJ and C3H/HeN mice (5,6-dimethyl-XAA greater than 5-methyl-XAA greater than FAA greater than XAA greater than 8-methyl-XAA). Recombinant human TNF-alpha stimulated nitric oxide production equally from both murine strains while endotoxin stimulated nitric oxide production only by C3H/HeN mice. The extent of induction of haemorrhagic necrosis in tumour-bearing mice treated with FAA, 5,6-dimethyl XAA or endotoxin paralleled the effects on nitric oxide production, showing a differential between the two strains of mice only in the case of endotoxin.

Animals↗
PubMed2001

Characterization of acetic acid bacteria in traditional acetic acid fermentation of rice vinegar (komesu) and unpolished rice vinegar (kurosu) produced in Japan.

Bacterial strains were isolated from samples of Japanese rice vinegar (komesu) and unpolished rice vinegar (kurosu) fermented by the traditional static method. Fermentations have never been inoculated with a pure culture since they were started in 1907. A total of 178 isolates were divided into groups A and B on the basis of enterobacterial repetitive intergenic consensus-PCR and random amplified polymorphic DNA fingerprinting analyses. The 16S ribosomal DNA sequences of strains belonging to each group showed similarities of more than 99% with Acetobacter pasteurianus. Group A strains overwhelmingly dominated all stages of fermentation of both types of vinegar. Our results indicate that appropriate strains of acetic acid bacteria have spontaneously established almost pure cultures during nearly a century of komesu and kurosu fermentation.

Acetic Acid↗
PubMed1997

Increased plasma serotonin following treatment with flavone-8-acetic acid, 5,6-dimethylxanthenone-4-acetic acid, vinblastine, and colchicine: relation to vascular effects.

A number of antitumor agents are known to cause selective reduction in tumor blood flow, leading in some cases to tumor necrosis and growth delay. These agents include flavone acetic acid (FAA), an antitumor agent with high experimental but no clinical antitumor activity, 5,6-dimethylxanthenone-4-acetic acid (DMXAA), a highly active analogue of FAA, endotoxin, vinblastine, and colchicine. We find here that plasma concentrations of serotonin (5-hydroxytryptamine) and its metabolite 5-hydroxyindole acetic acid (5-HIAA) are increased following administration of these agents. Mice were injected with each at the maximum tolerated dose and, at various times later, blood samples were taken, cells and platelets removed by centrifugation, and serotonin and 5-HIAA concentrations were measured by high performance liquid chromatography. FAA and DMXAA induced six- and sevenfold increases in serotonin and 5-HIAA, respectively, with maximal levels 4 h after drug administration. 8-Methylxanthenone-4-acetic acid, an inactive analogue of DMXAA, failed to increase serotonin and caused only a small increase in 5-HIAA. Endotoxin, vinblastine, and colchicine each caused increases in serotonin and 5-HIAA between 2 and 6 h after drug administration. The mitotic poison paclitaxel, despite inducing growth delays of Colon 38 tumors, did not induce tumor necrosis and caused no increase in serotonin or 5-HIAA up to 6 h. The effect of the presence of subcutaneous Colon 38 tumors was tested and found not to affect the induction of increases in serotonin and 5-HIAA by DMXAA and colchicine. We suggest that the increases in plasma serotonin and its metabolite are a result of drug-induced vascular effects in host tissues, and that measurement of these compounds provides a potential means of monitoring drugs exerting vascular effects.

Animals↗
PubMed2004

Characterization of fluxional hydrogen-bonded complexes of acetic acid and acetate by NMR: geometries and isotope and solvent effects.

1H, (2)H, and (13)C NMR spectra of enriched CH(3)(13)COOH acid without and in the presence of tetra-n-butylammonium acetate have been measured around 110 K using a liquefied Freon mixture CDF(3)/CDF(2)Cl as a solvent, as a function of the deuterium fraction in the mobile proton sites. For comparison, spectra were also taken of the adduct CH(3)(13)COOH.SbCl(5) 1 and of CH(2)Cl(13)COOH under similar conditions, as well as of CH(3)(13)COOH and CH(3)(13)COO(-) dissolved in H(2)O and D(2)O at low and high pH at 298 K. The low temperatures employed allowed us to detect several well-known and novel hydrogen-bonded complexes in the slow hydrogen bond exchange regime and to determine chemical shifts and coupling constants as well as H/D isotope effects on chemical shifts from the fine structure of the corresponding signals. The measurements show that self-association of both carboxylic acids in Freon solution gives rise exclusively to the formation of cyclic dimers 2 and 3 exhibiting a rapid degenerate double proton transfer. For the first time, a two-bond coupling of the type (2)J(CH(3)COOH) between a hydrogen-bonded proton and the carboxylic carbon has been observed, which is slightly smaller than half of the value observed for 1. In addition, the (1)H and (2)H chemical shifts of the HH, HD, and the DD isotopologues of 2 and 3 have been determined as well as the corresponding HH/HD/DD isotope effects on the (13)C chemical shifts. Similar "primary", "vicinal", and "secondary" isotope effects were observed for the novel 2:1 complex "dihydrogen triacetate" 5 between acetic acid and acetate. Another novel species is the 3:1 complex "trihydrogen tetraacetate" 6, which was also characterized by a complex degenerate combined hydrogen bond- and proton-transfer process. For comparison, the results obtained previously for hydrogen diacetate 4 and hydrogen maleate 7 are discussed. Using an improved (1)H chemical shift-hydrogen bond geometry correlation, the chemical shift data are converted into hydrogen bond geometries. They indicate cooperative hydrogen bonds in the cyclic dimers; i.e., widening of a given hydrogen bond by H/D substitution also widens the other coupled hydrogen bond. By contrast, the hydrogen bonds in 5 are anticooperative. The measurements show that ionization shifts the (13)C signal of the carboxyl group to low field when the group is immersed in water, but to high field when it is embedded in a polar aprotic environment. This finding allows us to understand the unusual ionization shift of aspartate groups in the HIV-pepstatin complex observed by Smith, R.; Brereton, I. M.; Chai, R. Y.; Kent, S. B. H. Nature Struct. Biol. 1996, 3, 946. It is demonstrated that the Freon solvents used in this study are better environments for model studies of amino acid interactions than aqueous or protic environments. Finally, a novel correlation of the hydrogen bond geometries with the H/D isotope effects on the (13)C chemical shifts of carboxylic acid groups is proposed, which allows one to estimate the hydrogen bond geometries and protonation states of these groups. It is shown that absence of such an isotope effect is not only compatible with an isolated carboxylate group but also with the presence of a short and strong hydrogen bond.

Journal Article↗
PubMed1994

Combining bioreductive drugs (SR 4233 or SN 23862) with the vasoactive agents flavone acetic acid or 5,6-dimethylxanthenone acetic acid.

PURPOSE: To determine whether 5,6-dimethylxanthenone acetic acid (DMXAA), a potent analogue of flavone acetic acid (FAA) inhibits blood flow in mouse mammary tumors, and to assess whether DMXAA enhances the antitumor effects of Tirapazamine (SR 4233) and the novel bioreductive drug SN 23862 (a dinitrobenbenzene mustard). METHODS AND MATERIALS: MDAH-MCa-4 mouse mammary tumors were grown i.m. in the leg of C3H/HeN mice. Tumor blood flow was assessed by the pertechnetate clearance method and subsequent growth delay was determined in the same tumors. RESULTS: Administration of DMXAA (65-70 mumol/kg) resulted in inhibition of tumor blood flow to approximately 25% of control values, with no recovery observed up to 36 h post-treatment. Combination of DMXAA with SR 4233 provided a significant increase in tumor growth inhibition relative to either drug alone. In this effect, DMXAA was qualitatively similar to FAA, but was approximately 10 x more potent. The interaction between DMXAA (65 mumol/kg) and SR 4233 (200 mumol/kg) was maximal with SR 4233 given between 15 min before and 60 min after DMXAA. For SN 23862, a similar enhanced growth delay was observed in combination with DMXAA, with no obvious time dependence between 15 min before and 4 h after DMXAA. When mean values for groups treated with SR 4233 (200 mumole/kg) alone and in combination with DMXAA (65-90 mumole/kg) were compared, a correlation was observed between tumor blood flow inhibition and subsequent growth delay. CONCLUSION: DMXAA is a potent inhibitor of blood flow in MDAH-MCa-4 tumors. Combination of this vasoactive drug with bioreductive agents leads to an enhanced antitumor effect. For SR 4233 and DMXAA, this enhanced effect may be predictable by measurement of tumor blood flow inhibition shortly after drug administration.

Aniline Mustard↗
PubMed1999

Inhibition of DT-diaphorase (NAD(P)H:quinone oxidoreductase, EC 1.6.99.2) by 5,6-dimethylxanthenone-4-acetic acid (DMXAA) and flavone-8-acetic acid (FAA): implications for bioreductive drug development.

The tumour blood flow inhibitors 5,6-dimethylxanthenone-4-acetic acid (DMXAA) and flavone-8-acetic acid (FAA) have been shown to potentiate the antitumour activity of several bioreductive drugs in vivo. Whilst the induction of hypoxia as a result of blood flow inhibition is presumed to be responsible for enhancing the activity of bioreductive drugs, no studies have examined potential interactions between DMXAA or FAA and enzymes involved in bioreductive drug activation. Both FAA and DMXAA are competitive inhibitors of the enzyme DT-diaphorase (NAD(P)H:Quinone oxidoreductase EC 1.6.99.2) with respect to NADH, with Ki values of 75 and 20 microM, respectively. Cytochromes P450 reductase and b5 reductase activities are not significantly inhibited by FAA, whereas DMXAA partially inhibits cytochrome b5 reductase activity. The cytotoxicity of the indoloquinone EO9 (3-hydroxymethyl-5-aziridinyl-1-methyl-2-[1H-indole-4,7-dione] prop-beta-en-alpha-ol) against DLD-1 (IC50 = 0.32+/-0.08 microM) was significantly reduced when combinations of EO9 and FAA (IC50 = 12.26+/-5.43 microM) or DMXAA (IC50 > 40 microM) were used. In the case of menadione (which is detoxified by DT-diaphorase), combinations of menadione with FAA or DMXAA were more toxic (IC50 = 7.46+/-2.22 and 9.46+/-1.70 microM, respectively) than menadione alone (IC50 = 22.02+/-1.59 microM). Neither DMXAA nor FAA potentiated the activity of tirapazamine in vitro. These results suggest that the use of DMXAA and FAA to potentiate the activity of bioreductive drugs where DT-diaphorase plays a central role in either activation or detoxification may be inappropriate. The fact that FAA in particular does not inhibit other key enzymes involved in bioreductive activation suggests that it may be useful in terms of identifying DT-diaphorase-activated prodrugs.

Antineoplastic Agents↗
PubMed1992

Nitric oxide: its production in host-cell-infiltrated EMT6 spheroids and its role in tumour cell killing by flavone-8-acetic acid and 5,6-dimethylxanthenone-4-acetic acid.

Flavone-8-acetic acid (FAA) and its more dose-potent analogue 5,6-dimethylxanthenone-4-acetic acid (5,6-MeXAA), appear to exert their antitumor effects through vascular and other host-mediated mechanisms and are known to induce the synthesis of nitric oxide by murine macrophages. We investigated the role of nitric oxide in the cytotoxic effects of these drugs in host-cell-infiltrated spheroids. EMT6 murine mammary adenocarcinoma cells were grown in culture to produce multicellular spheroids in vitro spheroids), which were then inoculated i.p. into mice. After 6 days the spheroids were removed ex vivo spheroids). Exposure to FAA (890 microM) and 5,6-MeXAA (80 microM) in vitro for 20 h increased nitrite concentrations to 6.7 and 9.7 nmol/spheroid, respectively, as compared with 0.7 nmol/spheroid in the absence of drug. FAA and 5,6-MeXAA did not increase nitrite production in in vitro spheroids in cells obtained by peritoneal lavage. However, mixed cultures of in vitro spheroids and peritoneal cells treated with 5,6-MeXAA produced nitrite (2.4 nmol/spheroid), indicating that interactions between host cells and tumour cells were important for induction. The effects of these drugs on ex vivo spheroids were prevented by co-incubation with NG-monomethyl-L-arginine, indicating that nitrite originated from the oxidation of L-arginine to nitric oxide. Cell sorting of disaggregated spheroids into EMT6 cells and Mac-1-positive macrophage populations indicated that both of these cell populations could be induced to synthesise nitric oxide by subsequent incubation with 5,6-MeXAA. Incubation of ex vivo spheroids with FAA and 5,6-MeXAA decreased the clonogenicity of EMT6 cells, and this effect was wholly (FAA) or partially (5,6-MeXAA) reversed by the presence of NG-monomethylarginine (250 microM). FAA and 5,6-MeXAA may therefore exert some of their cytotoxic effects on tumour cells through the production of nitric oxide.

Adenocarcinoma↗
PubMed1993

Flavone acetic acid and 5,6-dimethylxanthenone-4-acetic acid: relationship between plasma nitrate elevation and the induction of tumour necrosis.

Antitumour agents such as flavone acetic acid, xanthenone acetic acid (XAA), 5,6-dimethylxanthenone-4-acetic acid and tumour necrosis factor-alpha, following single dose administration to mice with colon 38 adenocarcinomas, induce tumour haemorrhagic necrosis and an elevation in plasma nitrate. The relationship between these two effects has been studied using firstly a series of methyl-substituted XAA derivatives with varying antitumour activity, and secondly the inhibitors NG-monomethyl-L-arginine (NMMA), N-nitro-L-arginine (NNA) and canavanine, which affect nitric oxide synthesis. Elevation of plasma nitrate resulting from the oxidation of L-arginine by nitric oxide synthase is inhibited by NNA rather than by NMMA or canavanine. The results demonstrate that tumour necrosis can be induced in the absence of a significant elevation of plasma nitrate.

Adenocarcinoma↗
PubMed1990

Enhancing cervical cancer detection using nucleic acid hybridization and acetic acid tests.

Acetowhitening of abnormal cervical epithelium has been suggested as an indicator of increased cervical cancer risk. The presence of human papillomavirus (HPV) types 16, 18, 31, 33 and 35 may also indicate increased cervical cancer risk. Hence, tests that detect these two abnormal conditions may augment that Papanicolaou smear (Pap test) as predictors of cervical cancer risk. The cohort consisted of 145 women aged 14 to 47 (mean 21 years) attending health clinics. Thirty women (20.6 percent) showed acetowhitening of the cervical epithelium following exposure to vinegar of 4-percent acetic acid content. Fourteen (9.6 percent) had a positive Pap test and 13 (9 percent) carried a cervical HPV infection as determined by the commercially available ViraPap and ViraType nucleic acid tests. Statistical analysis of the data showed a positive correlation between Pap, ViraPap and acetic acid tests results. The acetic acid test and the nucleic acid tests were the sole positive tests for 21 (14.5 percent) and nine (6.2 percent) women, respectively. Four women with negative Pap results were infected with HPV types previously shown to have an association with cervical intraepithelial neoplasias, carcinoma in situ and cervical cancer. The authors have concluded that the acetic acid and nucleic acid tests detect women at risk for cervical cancer who would not have been detected by the Pap test alone.

Acetates↗
PubMed1983

Liquid-chromatographic determination of indole-3-acetic acid and 5-hydroxyindole-3-acetic acid in human plasma.

We describe a "high-performance" reversed-phase liquid-chromatographic method for determination of indole-3-acetic acid (I) and 5-hydroxyindole-3-acetic acid (II) in human plasma. I is eluted at 1.0 mL/min with a mixture of 1-pentanesulfonic acid (pH 3.1), methanol, and water. It is detected by fluorometry. A mixture of citric acid/sodium phosphate solution (pH 4.8) and methanol, at 1.5 mL/min, is used to elute II, which is detected with an electrochemical cell. Platelet-poor plasma samples were pretreated with HCl, perchloric acid, and trichloroacetic acid for protein precipitation. Best results were obtained with the last (protein precipitation is incomplete with HCl, while recoveries of I are concentration dependent with perchloric acid). Analytical recoveries were 58% (SD 3.1%, CV 5.3%, n = 12) and 79% (SD 3.3%, CV 5.3%, n = 9) for I and II, respectively. Concentrations of I and II in plasma ranged from 0.61 to 3.32 (mean 1.54, SD 0.59, n = 15) mumol/L and from 33.0 to 102.6 (mean 51.8, SD 20.1, n = 16) nmol/L, respectively.

Adult↗
PubMed1986

Boron and ectomycorrhizal influences on indole-3-acetic acid levels and indole-3-acetic acid oxidase and peroxidase activities of Pinus echinata Mill. roots.

The level of indole-3-acetic acid (IAA) in shortleaf pine (Pinus echinata Mill.) roots was increased by inoculation with the ectomycorrhizal fungus Pisolithus tinctorius (Pers.) Coker and Couch. Indole-3-acetic acid oxidase activity was also increased suggesting that the increased level of IAA was the result of increased synthesis. Boron fertilization reduced IAA levels in roots inoculated with P. tinctorius but not in noninoculated roots.

Journal Article↗